Smallish forms, 4 to 45 mm., with cuticle thickened on each side for the whole length of body in the form of a lateral flange or wing. Œsophagus long with a well-marked bulb containing a valvular apparatus. Tail end of female drawn out into a long point. Eggs asymmetrical. Males very small (about 2 mm.). One spicule. Genera: Oxyuris, Passalurus, Ozolaimus, Atractis, etc.
Mermithidæ, greatly elongated “Nematodes,” which, in the larval stage, are parasitic in insects, but in their adult condition are free living. Cuticle with diagonal striation. Without an open mouth or anus. Oral papillæ present. Characteristic eggs with two processes, ending in a tuft of filaments. Larvæ with a movable boring spine at the head end.
Gordiidæ.—Long, thread-like “Nematodes.” Mouth and anterior portion of gut atrophied in adult. Oral papillæ absent.
The Nematodes Observed in Man.
| Family | Sub-family | Genus | Species |
| Anguillulidæ | — | Rhabditis | R. pellio. |
| | | R. niellyi. |
| | | Rhabditis sp. |
| | Anguillula | A. aceti. |
| | Anguillulina | A. putrefaciens. |
| Angiostomidæ | — | Strongyloides | St. stercoralis. |
| Gnathostomidæ | — | Gnathostoma | Gn. siamense. |
| | | Gn. spinigerum. |
| Dracunculidæ | — | Dracunculus | D. medinensis. |
| Filariidæ | Filariinæ | Filaria | F. bancrofti. |
| | | F. demarquayi. |
| | | F. taniguchi. |
| | | F. (?) conjunctivæ. |
| Group. | Agamofilaria | — | Ag. georgiana. |
| | | Ag. palpebralis. |
| | | Ag. oculi humani. |
| | | Ag. labialis. |
| | | F. (?) romanorum-
orientalis. |
| | | F. (?) kilimaræ. |
| | | F. (?) sp. ? |
| | (Mikrofilaria) | Mf. powelli. |
| | | Mf. philippinensis. |
| | Setaria | S. equina. |
| | Loa | L. loa. |
| | Acanthocheilonema | Ac. perstans. |
| | Dirofilaria | Di. magalhãesi. |
| Onchocercinæ | Onchocerca | O. volvulus. |
| Trichinellidæ | Trichurinæ | Trichuris | T. trichiura. |
| Trichinellinæ | Trichinella | T. spiralis. |
| Dioctophymidæ | — | Dioctophyme | D. gigas. |
| Strongylidæ | Metastrongylinæ | Metastrongylus | M. apri. |
| Trichostrongylinæ | Trichostrongylus | T. instabilis. |
| | | T. probolurus. |
| | | T. vitrinus. |
| | Hæmonchus | H. contortus. |
| | Mecistocirrus
(Nematodirus) | M. fordi. |
| Ancylostominæ | | |
| Group. | Œsophagostomeæ | Ternidens | T. deminutus. |
| | Œsophagostomum | Œ. brumpti. |
| | | Œ. stephanostomum
var. thomasi. |
| | | Œ. apiostomum. |
| Group. | Ancylostomeæ | Ancylostoma | A. duodenale. |
| | | A. ceylanicum. |
| | | A. braziliense. |
| Group. | Bunostomeæ | Necator | N. americanus. |
| | | N. exilidens. |
| Group. | Syngameæ | Syngamus | S. kingi. |
| Physalopteridæ | — | Physaloptera | P. caucasica. |
| | | P. mordens. |
| Ascaridæ | Ascarinæ | Ascaris | A. lumbricoides. |
| | | A. sp. |
| | | A. texana. |
| | | A. maritima. |
| | Toxascaris | T. limbata. |
| | Belascaris | B. cati. |
| | | B. marginata. |
| | Lagocheilascaris | L. minor. |
| Oxyuridæ | — | Oxyuris | O. vermicularis. |
| Mermithidæ | — | Mermis | M. hominis oris. |
| | (Agamomermis) | Ag. restiformis. |
Family. Anguillulidæ.
Genus. Rhabditis, Dujardin, 1845.
Buccal cavity elongated, with lips. Its chitinous wall uniformly thick. Lateral lines absent. Males with bursa.
Rhabditis pellio, Schneider, 1866.